1. Field of the Invention
The present invention relates to a method and apparatus for monitoring temperature by continuously detecting a temperature distribution on an iron skin surface of a blast furnace facility such as a blast furnace body and a hot-air oven to achieve security of the facility, and relates to a temperature control system using the temperature monitor apparatus.
2. Description of the Prior Art
In the hot-air oven for heating air to be supplied into a blast furnace which constitutes the blast furnace facility, the combustion of gas and the blast of high-pressure air are alternately repeated in the inside of the hot-air oven. For this reason, as shown in FIG. 2, an inner wall of the hot-air oven is covered by heat-resistant bricks R, and the outer surface is covered by an iron skin 1 made of iron. Here, in particular, since the iron skin is an important structural member to cover the whole of the hot-iron oven, it is designed to have sufficient strength to resist high temperature and high pressure.
However, during the operation of the hot-air oven, when a part of the heat-resistant bricks on the inner wall is damaged or falls off due to thermal fatigue or the like, the iron skin of this area will be exposed to high temperature air in the oven. In this case, there is a fear that the portion of the iron skin corresponding to the exposure will be red heated, and in the worst case, a crack is will be caused and the hot air in the oven will blow out to the outside.
In order to prevent such an abnormal situation beforehand, in the prior art method disclosed, for example, in Japanese Utility Model Laid-Open Publication No. 60-29248, thermometers are mounted on the surface of the iron skin, and the monitor is carried out by a method of predicting an abnormal situation of this kind from a change in temperature. Specifically, temperature sensors such as thermocouples are mounted on suitable positions of the surface of the iron skin to enable to find out a temperature rise due to the occurrence of red heat at an early stage.
However, in the prior art monitor method using the thermocouples involves a drawback in that the temperature is measured only at the "points" at which the thermocouples are mounted. If the whole surface of the iron skin constituting the outer wall of the hot-air oven is to be monitored by the prior art method using the thermocouples, several thousands of thermocouples must be mounted over the outer wall, and the practical use has never been achieved in view of the cost and workability.
For this reason, in the prior art monitor method, only the temperature has been monitored by disposing the thermocouples on the iron skin at essential points of several points to at most several tens of points. However, it is far insufficient to monitor the whole of the hot-air oven when the number of measurement points is in the above-mentioned order, and even when the object of the monitor is limited to a weld line at which the possibility of occurrence of crack is relatively high, it is impossible to cover the whole area, and thus it is not sufficient as the monitor method.
Furthermore, as to the blast furnace body, since the abnormal temperature on an outer surface reduces the life of the iron skin provided on the outer surface of the blast furnace facility, it is necessary to monitor the temperature of the iron skin also for the purpose of protecting the iron skin itself.
Accordingly, in the prior art, in order to monitor the temperature of the iron skin surface of the blast furnace body, a great number of high-temperature thermometers such as thermocouples are mounted on the whole surface of the iron skin of the blast furnace body.
Furthermore, Japanese Patent Publication No. 57-31073 discloses an apparatus for detecting positions at which the temperature is abnormally high by disposing a plurality of movable trucks about a blast furnace, and by measuring the temperature of the iron skin surface while moving the trucks each truck mounted with a radiation thermometer.
However, in the prior art method of measuring the temperature by mounting the high-temperature thermometers such as thermocouples on the iron skin surface, since a great number of thermocouples are needed, an enormous amount of installation cost is required, and many hours and manpower are required for inspection and maintenance. Regardless of such hours and manpower, the accuracy of finding the positions of occurrence of abnormally high temperature was not satisfactory.
Furthermore, in the monitor apparatus of iron skin surface disclosed in the above-mentioned Japaneses Patent Publication No. 57-31073, it is necessary to install around the blast furnace body a running gear of the trucks on which monitor units are mounted. However, it is difficult to install the running gear around the blast furnace in view of the available space since cooling water piping, a variety of gas pipings, cables, and iron frames are intricated around the blast furnace. Moreover, the cost of facilities for the running gear of the trucks and position detecting devices is expensive, and since the facility is complicated, many hours and manpower are required-for inspection and maintenance. In addition, an unsolved problem is involved in which the operation of the running gear of the trucks is difficult because the space around the blast furnace body is at high temperature, high humidity and high dust, and in an environment of CO gas.